In electronic instruments, wiring circuit boards are used and, with regard to the wiring circuit board, a flexible printed circuit board (may be sometimes called “FPC”) has been widely used. Usually, wiring circuit boards such as FPC are used in a state of being adhered to a reinforcing plate (such as aluminum plate, stainless steel plate or polyimide plate) and, at that time, a double-sided pressure-sensitive adhesive tape or sheet (double-sided pressure-sensitive adhesive tape or sheet for wiring circuit board) is used. With regard to such a double-sided pressure-sensitive adhesive tape or sheet, a double-sided pressure-sensitive adhesive tape or sheet having a constitution of being formed by adhesive layers only (the so-called “double-sided pressure-sensitive adhesive tape or sheet without substrate”) has been widely used in view of the total thickness. However, since the double-sided pressure-sensitive adhesive tape or sheet without substrate has no substrate, it is not suitable for fine perforating process. Moreover, there is a problem in the conventional double-sided pressure-sensitive adhesive tape or sheet that, especially under the conditions of high temperature and high humidity, the cut sides are adhered again (self-adhesion) after being perforated whereby working ability lowers. Further, in the worst case, it sometimes happens that, in detaching the perforated product, a part where an adhesive is deficient is resulted.
Although it has been attempted that, in the adhesive layer, the insoluble matter in solvent is enhanced for preventing the self-adhesion of the cut sides (refer to Patent Document 1), there is a problem that, when the matter which is insoluble in a solvent is enhanced, the adhesive layer is peeled off from the adherend when the part on which repulsive force acts is adhered.
On the other hand, in wiring circuit board such as FPC, there are some cases where a high-temperature step such as a solder reflow step is conducted but, when a part on which a repulsive force is applied is adhered after the solder reflow step, a problem that the adhesive layer is peeled off from the adherend sometimes happens.
Patent Document 1: JP-A-2001-40301